Drilling method for mining thin ore bodies



Jan. 26, 1965 MACAUL ETAL 3,167,354

DRILLING METHOD FOR MINING THIN ORE BODIES 2 Sheets-Sheet 1 OriginalFiled Sept. 7, 1961 IO /N /QO i/ TWA we? w INVENTORS ROBERT 7. MACAULDAN/EL J. DONOVAN ATTORNEY 2 Sheets-Sheet 2 bt .l u 3 NW mm I. I MN ow lI w A Y d m W m Vm J N A 8 m? T m M w m 2 3 Q m .I m QM .VQ fin H m L II? v L M M v an H I I ll 0 VI 3% F I l .H W v R m B mm mm 1965 R. T.MACAUL ETAL DRILLING METHOD FOR MINING THIN ORE BODIES Original FiledSept. 7, 1961 United States Patent 3,167,354 DRILLING METHOD FOR MININGTHIN ORE BODIES Robert T. Macaul, New York County, N .Y., and Daniel J.Donovan, Clifton, N.J., assignors to Ingersoll-Rand Company, New York,N.Y., a corporation of New Jersey Continuation of application Ser. No.136,491, Sept. 7,

1961. This application Aug. 24, 1962, Ser. No. 219,333 6 Claims. (Cl.299-11) This application is a continuation of US. patent applicationSerial No. 136,491, filed September 7, 1961, by Robert T. Macaul andDaniel J. Donovan, and entitled Method of Extracting and RecoveringMinerals from Veins Thereof.

This invention relates to methods of drilling and particularly tomethods for mining very thin ore bodies.

In certain sections of the earth there are vast deposits of valuable orein very thin veins ranging from less than one inch to perhaps six inchesor more in thickness which have been profitably mined largely because oflow labor costs. The systems employed for removing the ore have been toexcavate not only the material from the vein but material above andbelow to a depth which would enable the miner to enter to follow thevein. Often, the vein itself is of a very hard material such asquartzite and the like and the strata in which the vein lies is likewisehard. Drilling is usually employed to form blast holes and is followedby the usual blasting and mucking operations. Obviously, this entailsmuch labor and loss of time while blasting and mucking and cleaning upthe valuable metal bearing dust as fine cuttings. In addition a greatdeal of material of no value whatsoever has to be removed from the mineand in addition, the roof of the excavation has to be supported toprevent caving. Also it can happen that the blasting pulverizes the oreto such an extent that it is diflicult or sometimes impossible torecover.

It is an object of this invention to eliminate many of the operationsabove referred to and to limit as far as may be possible the excavationto removal of the valuable vein material and such of the adjacent rockof value.

In the improved embodiment of this invention the elimimination of thenumerous drilling operations isaccomplished by a continuous process ofdrilling holes that embrace all of the valuable material and very littleelse.

In order to set up the equipment for proceeding with this method a shaftis sunk from the surface to the level of the vein and a drift isexcavated along the face of the ore vein any convenient length dependingupon the extent of the mine property. Then drifts are excavatedtransverse to the first drift preferably parallel to each other and atconvenient intervals as for instance one hundred feet. The transversedrifts are excavated at the slope of the ore body and are of suitabledimensions to accommodate a drill directed at the vein. Holes aredrilled by a drill rig centering on the vein and of a diameter tooverlap it. Drilling proceeds until the drill hole reaches the nextadjacent transverse drift.

Preferably, the drilling is done with a core drill and preferably of atype delivering hammer blows to the bottom of the hole. This isgenerally advantageous because the rock is chipped out in relativelylarge pieces and the drilling proceeds faster. As the drilling proceeds,from time to time additional lengths of core barrel have to be addedand, if desired, the core may be extracted periodically and passeddirectly into a suitable car which when loaded can be removed andreplaced by an empty. The dust and chips formed by the drilling containvaluable ore often the most valuable and are collected by vacuumapparatus depositing the same in a filter which may be separate or ifdesired integral with the car carrying away the cores. Upon completionof the first hole, successive holes parallel to the first are drilledand preferably they overlap so as to remove all of the vein material.The system is continuous, the only interruption being due to theextension of the transverse drifts which may require blasting andmucking operations. However, such extensions of the drifts can becarried on, while the ore extraction process continues in others, sothat for all practical purposes the process is continuous.

A suitable layout for carrying out the mining method is illustrated inthe accompanying drawing in which FIGURE 1 illustrates an earth sectionindicating the vein of ore and the shaft and drift leading to it,

FIGURE 2 is a diagrammatic plan of the drifts excavated and theirrelation to the ore vein,

FIGURE 3 shows an end view of the vein, and indicates the plan of holesto be bored for extracting the ore,

FIGURE 4 is a view indicating the type of apparatus employed fordrilling the holes and associated machinery;

FIGURE 5 is a perspective view partly in section of an earth formationand plugging process adaptable to a modified process of drilling, and

FIGURE 6 is a perspective view of a rock formation to which stillanother modified method of drilling is applied.

Referring to the drawings the earths surface indicated at 10 ispenetrated by a vertical shaft 12 leading to the level of the vein 14 ofore to be removed. As shown, near the shaft a horizontal drift 16extends to vein 14 as it is generally considered desirable that there bea short level section to facilitate loading and handling of the materialin the horizontal section. To facilitate loading and raising in shaft12, a suitable hoist indicated at 18 is provided.

In FIGURE 2, as indicated, a cross drift 20 is excavated at about apoint where drift 16 reaches the vein 14-. Drift 20 extends any suitablelength following vein 14 and preferably at an angle at which vein 14would be level as indicated. Then, at suitable intervals of perhaps onehundred feet, in some cases, transverse drifts 22, 24 and 26 areexcavated following the slope of vein 14. It is astonishing that in manyplaces veins such as that indicated at 14 will extend for miles withoutmaterial variation in their inclination.

As described above, this method proposes to drill a series of holes asindicated in FIGURE 3 at 28, that at 28' being indicated in process ofdrilling. Holes 28 over lap one another and they are of suflicientdiameter to' cover not only the depth of the vein 14 but additionalmaterial above and below the vein.

It is understood that in deposits of this kind a certain lesser amountof valuable ore exists in the strata closely adjacent the main ore body.Holes 28 will be drilled from one of the transverse drifts to the othernext adjacent. Drilling straight holes is not a great problem. For onething the greater hardness of the vein mtaerial often assists in keepingthe drill centered if the drilling is by coring.

FIGURE 4 indicates the manner inwhich the apparatus 'is set up in adrift 24. As shown, the drill is of the rotary percussive type as shownat 30 and is provided with a long core barrel 32 extending into the hole28 and terminating at a bit 34 set with hard metal adapted to strike thebottom of the hole and chip and abrade out cuttings. Cuttings of thetype thus produced will contain valuable material which is recovered bymeans of a dust collector in the form of a suitable container 36preferably held close to the mouth of the hole 28'. From container 36the cuttings are removed by a suitable flexible tube 38 to a filter 40fitted with a suitable vacuum pump 42. Drill 30 is adapted to beadvanced on guides Patented Jan. 26, 1965 whicli'in this instance areformed by the flanges 44 of a pair of channels 46 (only one of Which isshown) ar-' ranged back to back and mounted on a suitable adjustablerotatable base 47 which is slidably mounted on a bar 48,. In thisinstance, the bar 48 is pivotally'mou'nte'd as at 50 on abase 52 so thatits slope may be adjusted to correspond to the slope" ofthevein. By thisarrangement a number of holes 28 can be made without moving the base 52.When moving becomes necessary, however, the I Wheels 54 supporting baseSZ permit suchmoving. When a proper location of base 52 is establishedit is preferable to provide a solid' support ,for which spuds 56' at thecorners of base 52 can be set up while a column58 which 7 is likewisemounted on base 52 is'adapted to further steady the assembly by clampingagainstflthe roof of the drift 24. Y

For convenience in carrying away the ore removedit may be desirable toprovide an enclosed car 60 on. suitable wheels 62 for placement at therear of drill 30. Such a car can be adapted to receive pieces of coresuch as 4. I the vacated space by suitable plugas indicated at 75 willaccomplish the result'and' purpose indicated above.

It is also understood -that'the drilling can be either W6t-OI fdry.Also, the line cuttings may be removed by blowing, sucking orwashingfrom drill holes. The

'manner of collecting the cuttings can be varied at option of user. V I

While in accordance with the patent statutes a preferred embodiment ofthe presentinvention'has been illustrated and described in detail, it isto be particularly understood that the invention is not limited theretoor-thereby.

We claim: I 1

1. A method of mining-a thin vein of ore comprising sinking a shaft tothelevel of said vein, excavating a cros'sdrift along said vein,excavating'dri'fts at intervals transverse to the'cross drift, drillinga series of overlapping parallel holes of diameter slightly in excess ofthe vein thickness and crosswise thereofbetween an adjacent pair ftransverse drifts to include substantially all of the vein that shown at64' and for that purpose arearward tube 66 "v as a continuation ofcorebarrel 32 can extend into the interior of car 60. Car 60 may beenclosed all around although this would not seem to be essential in viewof the fact that the dust collecton36 should have cleaned the corepieces 64 of looseparticles. The drilling apparatus shown is not onlyuseful for cutting cores between the transverse drifts but may be usedto cut similar cores from the faces of the transverse drifts prior toadvancing the drift. For that purpose, of course,

the drill rig would be turned at'a'n angle of 90 to the position shownin FIGURE 4 so as to cut in the direction.

' drifts as a source of crushed rock.

From the above it will-be seen that this method of mining willenormously reduce the labor involved in. the

I usual drilling operations aswell as mucking. In addition,

the time saved in drilling blast holes, blasting and mucking is to alarge extent eliminated and the operation becomes substantiallycontinuous.

Itwill be understood that the method ofmining. of this 1 invention isapplicable generally to a great many situa' tions such as for instancesurface deposits, for example coal stripping, asbestos mining, and manyothers. t

In underground applications, other typesof drilling" may be used asindicated in FIGURE 5 and FIGURE 6..

In FIGURE 5 are indicated a line of overlapping holes 70 which may bedrilled by a drill (not shown) which is adapted to enter the hole beingformed and has ashort bit which pulverizes all of the rockbeing removed.Such it is quite important that the roofmaterialv therebetween, andcollecting the material cut therefrom.

2. A method of mining a thin vein of ore comprising sinking ashafttothelevel' of said vein, excavating a cross drift along said vein,excavating drifts'at intervals transverse to' the cross drift, andcoredrilling a series of overlapping parallel holes of diameter slightlyin excess ofthe vein and crosswise thereof between an adjacent pair oftransverse drifts to include substantially all of the vein material, andcollecting the material cut therefrom.

3. Amethod of'mining anarrow veinof ore comprising sinking ashaft' tothe level of said vein, excavating a cross drift acmsssaid vein,excavating drifts at intervals transverse to the .cross drift, coredrilling a series of circular overlapping parallel holes of diameterslightly in excess of the vein and crosswise thereof between an adjacentpair of transverse drifts to include .allof the vein material, and

removing thecore as the drilling progresses.

4. A method of mining a narrow vein of ore comprising sinking a shaft tothe level of saidvein, excavating a cross driftalong said vein,excavating drifts at intervals transverse,tothe'crossxdrift,coredrillinga series of circular,

overlapping parallel holes of diameter, slightly in excess ofthelvcinand crosswise thereof between an adjacent pair of transversedrifts to include all of the vein material, and'withdrawing' the oreladen dust from the holes b'eing'drilled. V

* 5. A method'of mining a narrow vein of ore comprising sinking a shafttothe level of saidjvein, excavatingga cross drift along sai'djvein,excavating drifts at intervalstransversetothe. cross .dr ift,,Icoredrilling a series of overlapping,circulars-parallelholes ofdiameterslightly in ex cess ofthe 'vein' and crosswisethereof between;anadjacent pair of'transverse drifts to; include all of. the vein' mateadrill is illustrated in Morrison US. Patent 2,810,549,

of October 22, '1957. In-using such a drill the cuttings are generallycollected and they would'be in this instance also. In order to block offthe holes already drilled.

they may be filled with suitable plugs 7l-to prevent the entrance ofexcess air. correspond tothose illustrated in FIGURE3 Still anothermethod is shown in FIGURE 6 in which at the edges,-top and bottom of theseam 73 or thereabout a line of smaller holes 72 would be drilled as inthe well known method of line-hole drilling. The core The location ofthe holes would 74 remaining may be broken in'any suitable manner andremoved to recover the mineral of value. A suitable drill and mountingfor such use is described in Slater.

Patent 2,213,32 9f ,Sep 3, 0; The loc i g o rial, withdrawing the oreladen, dustfrom the holes being drilled, and removing the cores as thedrilling progresses. 6. .A'methodof mining anarrow vein'of orecomprising sinking a shaft to the level of s'aidvein,-excavating, across drift along.said.. vein, excavating drifts at intervals transverseto the'crossidrift, core drillingthe vein of ore between: saidtransverse drifts to form a slot from which the vein of, ore hasbeenextracted, and inserting plugs in the core drilled holes to support theoverburden.

References Cited by the Examiner UNITED STATES'PATENTS 444,476 1/91Wolford. j 981,201v 1 11" Kuhn. f,

1,495,474 5/24; letcher 17 558 2,698,169 12/ 54 v Fawkes. 2,940,740 6/60Adams.

BENJAMINHERSH, Primary Examiner,

1. A METHOD OF MINING A THIN VEIN OF ORE COMPRISING SINKING A SHAFT TOTHE LEVEL OF SAID VEIN, EXCAVATING A CROSS DRIFT ALONG SAID VEIN,EXCAVATING DRIFTS AT INTERVALS TRANSVERSE TO THE CROSS DRIFT, DRILLING ASERIES OF OVERLAPPING PARALLEL HOLES OF DIAMETER SLIGHTLY IN EXCESS OFTHE VEIN THICKNESS AND CROSSWISE THEREOF BETWEEN AN ADJACENT PAIR OFTRANSVERSE DRIFTS TO INCLUDE SUBSTANTIALLY ALL OF THE VEIN MATERIALTHEREBETWEEN, AND COLLECTING THE MATERIAL CUT THEREFROM.